A pneumo-hydraulic converter with reciprocating double piston which connects a compressed air storage and a hydraulic circuit at maximum efficiency in such a way that energy can flow into the storage (charging) or can be removed from the storage (discharging) is known.
The good efficiency of isothermal processes is obtained in the above system by stabilizing the temperature in the working chambers (piston spaces) during each stroke by means of the operating medium, i.e., oil. This will result in relatively slow working processes, since the limited velocity of the heat transfer from the lateral surface of the cylinder to the air during the working stroke cannot compensate the temperature fluctuations at increased cycle frequency. As a consequence, the structual units employed are comparatively large in relation to the power involved.
It is the object of this invention to achieve good efficiency while increasing the cycle frequency at the same time.